The present invention relates to an electrical connector for electrically and mechanically coupling an electrical connecting element in the form of a flat plate, such an FPC (Flexible Printed Circuits) or FFC (Flexible Flat Cables), to a printed circuit board (referred to as a circuit board hereinafter) through electrically-conductive contacts, and more particularly to an electrical connector having a joint structure adapted to connect an electrical connecting element to contacts by moving the element horizontally.
An electrical connector according to Prior Art 1 is constructed such that a slider member is inserted in the same direction as a direction in which the FPC is inserted, whereupon resilient contact portions of contacts are deformed so as to come into contact under reaction forces with electrically-conductive portions provided on a lower surface of an FPC. When the slider member is pushed into place horizontally in the same direction as the direction in which the FPC is inserted, the FPC is pressed downward by a pressing force applied from the slider member to it, and the resilient contact portions of the contacts are deformed through the FPC and sprung back to come into contact with the electrically-conductive portions of the FPC (See, e.g., Japanese Unexamined Utility Model Publication No. 6-7179).
There is also known a modification of the above electrical connector having such a structure that U-shaped contacts are employed and a movable piece is inserted in a direction opposite to the direction in which an FPC is inserted, causing the contacts to partly deform and spring back to come into contact with corresponding electrically-conductive portions which are provided on an upper surface of the FPC. (See, e.g., Japanese Unexamined Patent Publication No. 3-82563).
An electrical connector according to Prior Art 2 employs a pressing member rotatively fitted into place. An FPC is inserted into a gap between the pressing member and contact bosses of contacts before the pressing member is rotated. When pressing member is rotated, it comes closer to the contact bosses while pressing the FPC against the contact bosses, allowing the contact bosses to come into contact with electrically-conductive portions provided on the FPC. (See, e.g., Japanese Unexamined Patent Publication No. 7-142130 and Japanese Unexamined Utility Model Publication No. 6-77186).
As another example of prior art, there is an electrical connector in which substantially L-shaped contacts are displaced to apply a pressure to an FPC for holding it in a fitted state. Specifically, this electrical connector has such a structure that a plate is inserted into one surface side of the contacts from above to displace the contacts downward, whereupon the positions of contact bosses provided on the other surface side of the contacts are changed to such an extent as enough to hold the FPC in place with a satisfactory contact force (See, e.g., U.S. Pat. No. 5,542,855).
The structure of the electrical connector of Prior Art 1 has a problem that the FPC is liable to shift in its position because the slider member is pushed into place while sliding over the FPC and pressing it downward. More specifically, when the slider member is inserted into the housing, it simultaneously imposes a pressing or contact force upon the FPC, thus producing a force tending to shift the FPC in the direction of insertion. In alignment of the FPC and the housing, therefore, relative positions of the contact bosses and the electrically-conductive portions of the FPC are more likely to shift upon insertion of the slider member.
Accordingly, this type of electrical connector has a difficulty in design of making narrower the pitch of the plurality of contacts or thinner the FPC to enhance its strength for the purpose of arraying a larger number of contacts in the housing; hence it has a limit in reducing the size.
Another problem of the above electrical connector is below. An attempt to assemble the contacts in the housing at a higher density and realize a smaller size would necessarily reduce the size of the slider member. This requires a larger operating force to establish connection of a larger number of contacts with the FPC. As a result, the slider member becomes harder to push it into place and the working efficiency is deteriorated.
The structure of the electrical connector of Prior Art 2 has a problem that the contact bosses and the electrically-conductive portions of the FPC are liable to shift in relative position as with the electrical connector of Prior Art 1 because the FPC is also pressed by a force tending to rotate it with respect to the contact bosses.
A problem common to the structures of the electrical connectors of Prior Arts 1, 2 is that the height of the connector cannot be reduced. Specifically, both the connectors have such a structure that the FPC and the slider member or the pressing member are grasped by the U-shaped contacts, i.e., that pressing or contact forces are indirectly applied to the upper surfaces of the resilient contact portion. For this reason, an insulating member (housing) necessarily has a large thickness.
In the other electrical connector using the contacts which are not U-shaped but substantially L-shaped or the like, reaction forces produced upon the contact bosses being displaced to provide the contact forces must be borne by any of the components. Usually, an insulating member called a housing serves to bear such reaction forces. To this end, a wall of the insulating member serving to bear the reaction forces is required to have a sufficiently large thickness.
Further, the conventional electrical connectors have a difficulty in reducing the size because they necessarily have a large height as mentioned above. In addition, since the contact bosses of the electrical connector are displaced downward, it is required to provide a housing wall or the like in position outside the contact bosses. Accordingly, there is a problem that the electrical connectors have a relatively large overall size and are difficult to achieve a reduction in size.